LETTER XXVI. (VIII.)

[Simon de Vries, a diligent student of Spinoza's writings and philosophy, describes a club formed for the study of Spinoza's MS. containing some of the matter afterwards worked into the Ethics, and asks questions about the difficulties felt by members of the club. 2]

Most Honourable Friend,I have for a long time wished to be present with you; but the weather and the hard winter have not been propitious to me. I sometimes complain of my lot, in that we are separated from each other by so long a distance. Happy, yes most happy is the fellow-lodger, abiding under the same roof with you, who can talk with you on the best of subjects, at dinner,

at supper, and during your walks. 1 However, though I am far apart from you in body, you have been very frequently present to my mind, especially in your writings, while I read and turn them over. But as they are not all clear to the members of our club, for which reason we have begun a fresh series of meetings, and as I would not have you think me unmindful of you, I have applied my mind to writing this letter.

As regards our club, the following is its order. One of us (that is everyone by turn) reads through and, as far as he understands it, expounds and also demonstrates the whole of your work, according to the sequence and order of your propositions. Then, if it happens that on any point we cannot satisfy one another, we have resolved to make a note of it and write to you, so that, if possible, it may be made clearer to us, and that we may be able under your guidance to defend the truth against those who are superstitiously religious, and against the Christians, 2 and to withstand the attack of the whole world. Well then, since, when we first read through and expounded them, the definitions did not all seem clear to us, we differed about the nature of definition. Next in your absence we consulted as our authority a celebrated mathematician, named Borel: 3 for he makes mention of the nature of definition, axiom, and postulate, and adduces the opinions of others on the subject. But his opinion is as follows: "Definitions are cited in a demonstration as premisses. Wherefore it is necessary, that they should be accurately known; otherwise scientific or accurate knowledge cannot be attained by their means." And elsewhere he says: "The primary and most known construction or passive quality of a given subject should not be chosen rashly, but with the greatest care; if the construction or passive quality be an impossibility, no scientific definition can be obtained. For instance,

if anyone were to say, let two straight lines enclosing a space be called figurals, the definition would be of non-existences and impossible: hence ignorance rather than knowledge would be deduced therefrom. Again, if the construction or passive quality be possible and true, but unknown or doubtful to us, the definition will not be good. For conclusions arising from what is unknown or doubtful are themselves uncertain or doubtful; they therefore bring about conjecture or opinion, but not certain knowledge.

Jacquet 1 seems to dissent from this opinion, for he thinks that one may proceed from a false premiss directly to true conclusion, as you are aware. Clavius, 2 however, whose opinion he quotes, thinks as follows: "Definitions," he says, "are artificial phrases, nor is there any need in reasoning that a thing should be defined in a particular way; but it is sufficient that a thing defined should never be said to agree with another thing, until it has been shown that its definition also agrees therewith."

Thus, according to Borel, the definition of a given thing should consist as regards its construction or passive quality in something thoroughly known to us and true. Clavius, on the other hand, holds that it is a matter of indifference, whether the construction or passive quality be well known and true, or the reverse; so long as we do not assert, that our definition agrees with anything, before it has been proved.

I should prefer Borers opinion to that of Clavius. I know not which you would assent to, if to either. As these difficulties have occurred to me with regard to the nature of definition, which is reckoned among the cardinal points of demonstration, and as I cannot free my mind from them, I greatly desire, and earnestly beg you, when you have leisure and opportunity, to be kind enough to send me your opinion on the matter, and at the same time to tell me the distinction between axioms and definitions. Borel says that the difference is merely nominal, but I believe you decide otherwise.

Further, we cannot make up our minds about the third definition. 1 I adduced to illustrate it, what my master said to me at the Hague, 2 to wit, that a thing may be regarded in two ways, either as it is in itself, or as it is in relation to something else; as in the case of the intellect, for that can be regarded either under the head of thought, or as consisting in ideas. But we do not see the point of the distinction thus drawn. For it seems to us, that, if we rightly conceive thought, we must range it under the head of ideas; as, if all ideas were removed from it, we should destroy thought. As we find the illustration of the matter not sufficiently clear, the matter itself remains somewhat obscure, and we need further explanation.

Lastly, in the third note to the eighth proposition, 3 the beginning runs thus:"Hence it is plain that, although two attributes really distinct be conceived, that is, one without the aid of the other, we cannot therefore infer, that they constitute two entities or two different substances. For it belongs to the nature of substance, that each of its attributes should be conceived through itself, though all the attributes it possesses exist simultaneously in it." Here our master seems to assume, that the nature of substance is so constituted, that it may have several attributes. But this doctrine has not yet been proved, unless you refer to the sixth definition, of absolutely infinite substance or God. Otherwise, if it be asserted that each substance has only one attribute, and I have two ideas of two attributes, Î may rightly infer that, where there are two different attributes, there are also different substances. On this point also we beg you to give a further explanation. Besides I thank you very much for your writings communicated to me by P. Balling, 4 which have greatly delighted me, especially

your note on Proposition XIX. 1 If I can do you any service here in anything that is within my power, I am at your disposal. You have but to let me know. I have begun a course of anatomy, and am nearly half through with it; when it is finished, I shall begin a course of chemistry, and thus under your guidance I shall go through the whole of medicine. I leave off, and await your answer. Accept the greeting of

Your most devoted S. J. DE VRIES.

Amsterdam, 24 Feb., 1663.

Footnotes

309:1 For an account of Simon de Vries see Introduction, p. xiv. His letters are written in very indifferent Latin, which is, perhaps, one reason, why the present letter at least has been altered freely by the first editors.

309:2 The version of this letter in Bruder's and former editions is much altered by the omission of all mention of the club, and of the reference to Albert Burgh, and by the change throughout of the plural referring to the members of the club into the singular referring to the writer only. The genuine form here followed is to be found in Van Vloten's Supplementum.

310:1 This "fellow-lodger," again mentioned in the next letter, is pretty certainly Albert Burgh, concerning whom see Introduction, p. xv, and Letters LXXIII. and LXXIV

310:2 Van Vloten infers that the members of the club were chiefly Jews.

310:3 Peter Borel, born 1620, physician to the king of France, died 1689. He wrote several medical and philosophical works, and became in 1674 a member of the French Academy of Sciences.

311:1 Andrew Jacquet. born at Antwerp 1611, was mathematical professor in that town, died 1660.

311:2 Christopher Clavius, born at Bamberg 1537, was mathematical professor at Rome, died 1612.

312:1 The third definition of the Ethics, as they now exist. See p. 45.

312:2 Spinoza must, therefore, have visited the Hague before he lived there.

312:3 In the Ethics as they now exist, "in I. x. note, towards the beginning," to which reading the editors consequently altered the text, till the true reading was restored by Van Vloten.

312:4 Peter Balling is the correspondent, to whom Spinoza wrote Letter XXX., which see. He translated into Dutch Spinoza's Principia, as to which see Introduction, p. xv.

313:1 There is no note to Ethics, I. xix. As there is nothing to show what proposition is intended, the old version suppressed the whole passage from "Besides I thank you" to "medicine."